Thandarum hernandezi, a new genus and new species of sea cucumber family Sclerodactylidae (Echinodermata: Holothuroidea: Dendrochirotida) from the Southwestern Atlantic Ocean

A new genus and a new species of dendrochirotid, Thandarum hernandezi gen. et sp. nov., is described from Buenos Aires coast in the Southwestern Atlantic. For this species is quite significant the body U shape, up to 14.08 mm (along the trivium), with double row of podia restricted to the ambulacra. Other features are ossicles from body wall with buttons and 4 pillar tables, tube feet with rods and end plate star-shaped; the introvert with rosettes and tentacles with rods. These characteristics require the recognition of a new genus, and the new species and represents the first sclerodactylid reported in Argentinean waters.Fil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Brogger, Martin Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; Argentin

Echinoderms diversity in the Southwestern Atlantic

Studies of biodiversity of echinoderms from South America have increased in recent years. Here we summarize sampling done on three expeditions along the Argentinean coast (35º - 55º S) and near the Antarctic Peninsula. The first campaign, Mejillón II (M-II; 2009), was carried out between 35º - 39º S and covered a depth range between 10 to 140 m. The second was part of the Summer Antarctic Campaign 2011 (CAV-III; 2011) that took place around the Antarctic Peninsula, South Shetland and South Orkney Islands (depth range between 67 to 754 m). The last cruise was the final stretch of the Summer Antarctic Campaign 2011 (CAV-IV; 2011), from 39º - 55º S and between 30 - 140 m depth. As result, 74 stations have been studied, of which 68 had at least one echinoderm specimen. From the total number of stations, the occurrence percentages for each class were Asteroidea (68 %), Echinoidea (64 %), Ophiuroidea (55 %), Holothuroidea (51 %) and Crinoidea (20 %). In the M-II campaign, echinoderms were presented in 94 % of the sampled stations, with Echinoidea most frequent (74 %). In the CAV-III campaign echinoderms were presented in all the stations; Ophiuroidea were found in all stations. The lowest occurrence of echinoderms was found in the CAV-IV campaign (82 %), where Asteroidea was present in the 73 % of the samples, and crinoids were absent.Fil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Arribas, Lorena Pilar. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Berecoechea, Juan José. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Brogger, Martin Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Nacional Patagónico; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Corallimorpharians (Anthozoa: Corallimorpharia) from the Argentinean Sea

Corallimorpharians are a relative small group of anthozoan cnidarians, also known as jewel sea anemones. They resemble actiniarian sea anemones in lacking a skeleton and being solitary, but resemble scleractinian corals in external and internal morphology, and they are considered to be the sister group of the stony corals. Corynactis carnea (=Sphincteractis sanmatiensis) is a small, common and eye catching species that inhabits the shallow water of northern Patagonia and the Argentinean shelf up to 200 m depth. Corallimorphus rigidus is registered for the first time from the southwestern Atlantic Ocean. It is a rather big and rare species that inhabits only the deep sea. Only two specimens were found at 2934 m depth in Mar del Plata submarine canyon, in an area under the influence of the Malvinas current, which may explain its occurrence. These two species are the only two known jewel sea anemones in the Argentinean sea and are reported and described herein.Fil: Lauretta, Daniel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

A new species of Havelockia Pearson, 1903 from the Argentine Sea (Holothuroidea: Dendrochirotida: Sclerodactylidae)

Havelockia pegi sp. nov., is here described from shallow waters of the Argentine Sea. This new species is distinctive in the purple colouration of its tentacles, scarcity of body wall ossicles and the presence of rosette-shaped ossicles in both the introvert and the tentacles. It is not closely related to any of its congenors. This is the first record of a true sclerodactylid from Argentina. Thandarum hernandezi Martinez & Brogger, 2012, described in the family Sclerodactylidae, is now classified in the family Sclerothyonidae.Fil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; ArgentinaFil: Thandar, Ahmed. University of Kwazulu-Natal; SudáfricaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales; Argentin

Tooth microstructure and feeding biology of the brittle star <i>Ophioplocus januarii</i> (Echinodermata: Ophiuroidea) from northern Patagonia, Argentina

Ophioplocus januarii is a common brittle star on soft and hard substrates along the Argentinian and Brazilian coasts. Based on stomach contents, tooth microstructure and field observations we identified its food. Opposed to previous suggestions, O. januarii appears to be a microphagous species feeding on macroalgal fragments (found in 60.0 % of the analyzed stomachs with content), plant debris (28.0 %), animal cuticle structures (13.0 %), and unidentifiable material (30.7 %). Less frequent items found were foraminiferans, ostracods, an amphipod, a juvenile bivalve, and other crustaceans. Electronic microscope revealed digested material, diatoms and small crustacean appendices. Thus, O. januarii is an omnivorous species, feeding mainly on algae, complemented opportunistically with other items. Suspension feeding was observed in the field. It has an fenestrated arrangement intermediate between the previously described uniform and compound teeth.Facultad de Ciencias Naturales y MuseoInstituto de Investigaciones Bioquímicas de La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Tooth microstructure and feeding biology of the brittle star <i>Ophioplocus januarii</i> (Echinodermata: Ophiuroidea) from northern Patagonia, Argentina

Ophioplocus januarii is a common brittle star on soft and hard substrates along the Argentinian and Brazilian coasts. Based on stomach contents, tooth microstructure and field observations we identified its food. Opposed to previous suggestions, O. januarii appears to be a microphagous species feeding on macroalgal fragments (found in 60.0 % of the analyzed stomachs with content), plant debris (28.0 %), animal cuticle structures (13.0 %), and unidentifiable material (30.7 %). Less frequent items found were foraminiferans, ostracods, an amphipod, a juvenile bivalve, and other crustaceans. Electronic microscope revealed digested material, diatoms and small crustacean appendices. Thus, O. januarii is an omnivorous species, feeding mainly on algae, complemented opportunistically with other items. Suspension feeding was observed in the field. It has an fenestrated arrangement intermediate between the previously described uniform and compound teeth.Facultad de Ciencias Naturales y MuseoInstituto de Investigaciones Bioquímicas de La PlataConsejo Nacional de Investigaciones Científicas y Técnica

Brooding comatulids from the southwestern Atlantic, Argentina (Echinodermata: Crinoidea)

Isometra vivipara and Phrixometra nutrix are two brooding feather stars (order Comatulida) that are widely distributed along the southern tip of South America to the Antarctic. We examined 210 specimens of I. vivipara and 38 specimens of P.nutrix collected during five cruises in the southwestern Atlantic between 91 and 642 m depth. Specimens were analyzed and deposited in the National Invertebrate collection, Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”. Isometravivipara reaches an arm length of 49 mm long and shows two stages of brooding: in the female genital pinnules and on the cirri of the mother. In this paper, we propose that spermatozoa reach the ovary via the ambulacral groove. By contrast, P. nutrix is smaller with a maximum recorded size of 26.8 mm, and brooding occurs only inside the female genital pinnules. Here, we record, for the first time for P.nutrix, spermatozoa shape and a cleaved egg attached externally to a genital pinnule of a female. The distributions of both species and their abundances in some areas could be related to their doliolaria larval stage. In addition, we extend the bathymetric range of P.nutrix to 512 m in Marine Protected Area Namuncurá/Burdwood Bank and distribution to the Mar del Plata Submarine Canyon area. We also propose mode of reproduction and developmental patterns as attributes for identification and possible explanations for their differences in distribution.Fil: Pertossi, Renata Micaela. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchazadeh, Pablo E.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Universidad Simón Bolívar; VenezuelaFil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

First report of Paelopatides (Synallactida, Synallactidae) for the SW Atlantic, with description of a new species from the deep-sea off Argentina

The present study describes a new species, Paelopatides shumel n. sp., from Argentinian deep-sea waters. This is the first report of the order Synallactida for Argentina, the fifth for southern hemisphere and the deepest report for the Argentinian holothuroid fauna (almost 3000 m). The species has up to 330 mm length, light brown color and around 19 pairs of dorsal appendages. The ventral side has one ventral ambulacra, with two rows of tube feet. Ossicles are present in dorsal appendages, tube feet, tentacles and body wall near the anus, and are mainly crosses, tables and rods-shaped. The depth at which P. shumel n. sp. has been found is occupied by the North Atlantic Deep Water current. This association with North Atlantic waters could be related with the occurrence of members of Paelopatides in the North Atlantic.Fil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Solís Marín, Francisco A.. Universidad Nacional Autónoma de México; MéxicoFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Benthodytes violeta, a new species of a deep-sea holothuroid (Elasipodida: Psychropotidae) from Mar del Plata Canyon (south-western Atlantic Ocean)

A new species of elasipodid holothuroid, Benthodytes violeta sp. nov., is described from the Mar del Plata Canyon off Buenos Aires Province (around 38ºS–54ºW). It was taken at four locations at depths ranging from 1500 to 1950 m. This new species has a violet gelatinous body of up to 200 mm in length, with eight pairs of dorsal appendages, lateral festooned edges and four rows of tube feet ventrally. Body wall ossicles comprise rods and crosses with three or four arms and a central bipartite apophysis borne on the primary cross; tentacles and gonad deposits comprise rods and crosses with three and four arms. This is the first report of a holothuroid from the Mar del Plata Canyon area.Fil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Solís Marín, Francisco Alonso. Universidad Nacional Autónoma de México; MéxicoFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin

Brooding in the deep-sea sea anemone Actinostola crassicornis (Hertwig, 1882) (Cnidaria: Anthozoa: Actiniaria) from the southwestern Atlantic Ocean

Marine invertebrates can display several reproductive strategies, from external reproduction to parental care. Internal brooding is particularly relevant in harsh conditions, like Antarctic/sub-Antarctic waters and deep-sea, since it maximizes the survival of the young. Actinostola crassicornis is an abundant and widely distributed sea anemone from the southwestern Atlantic Ocean. It can be found all along the Argentinean sea down to 1200 m depth, usually in large numbers. It is a unique species in the area, since it is a large white brooding sea anemone. We studied 75 specimens collected by the O/V Walther Herwig and the O/V Puerto Deseado all along its distribution, from about 60 m to 800 m depth, in different seasons of the year. All the specimens were sexed, and the presence of free oocytes and juveniles inside the coelenteron were assessed. Large oocytes (over 500 μm) and juveniles were found in samples from most of the sampled months. We found a larger number of female specimens, and most of the brooding specimens were female. No early developmental stages were found smaller than a sea anemone with about 12 tentacles. We conclude that A. crassicornis reproduces continuously throughout the year and that although most of the juveniles were found in females, male specimens can breed. Brooding has great benefits in terms of protecting the offspring, since predation upon the juveniles is prevented, but dispersal of the offspring is low, shown by the aggregated distribution of the species.Fil: Lauretta, Daniel Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Vidos, Camila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Martinez, Mariano Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Penchaszadeh, Pablo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentin